These FTL experiments are various "tricks". In one type the phase velocity of light is prodded ahead of the group velocity. (It's the latter that carries information or energy or causal influences.) In another, an identical pulse leaves a chamber that is not really the original one entering it (that's lagging behind). In other set-ups, light is slowed down by the medium it enters, but charged particles (non-photons) are boosted by the medium so that they travel faster than the light that's been rendered sluggish. Et cetera. Consensus-wise, occasionally there may be unresolved controversy associated with a particular case.
There are
assorted circumstances where -- depending on the interpretative background concept applied to such -- the speed of light as measured in a vacuum may seem violated. But it's usually contended that information/casuality doesn't propagate beyond the cosmic speed limit when everything overall is vigorously assessed.